The meniscus is an anisotropic cartilaginous tissue of the knee that exists between the tibial plateau and the condyle of the femur. It supports the knee during motion and transmits loads through the joint. Meniscus injuries predominantly occur in young active males, usually during sport. Damage to the meniscus is the most common of all ligamentous or tendinous injuries, and accounts for 14.3% of injuries over 5 years in males with a mean age of 33.1 years . When these injuries occur they are life transforming events, disabling the individual, that can lead to lifelong complications and impaired function . The avascular tissue of the menisci has limited healing capacity and often the final treatment to restore function to a damaged joint is to remove the damaged meniscus. Removal of the menisci changes the mechanics of the knee, leading to instability of the joint and can contribute to the degradation of articular surfaces, all of which can be prevented if an adequate menisci replacement is found.
While allogeneic replacement of the menisci is the current gold standard, there is a shortage of suitable donor tissue. Tissue engineering aims to address the shortage of transplant tissues by regenerating lost, damaged, or diseased tissue either in vitro or in vivo. Briefly, cells are seeded into a degradable three dimensional scaffold that mimics extracellular matrix. Through the application of biochemical and mechanical cues, the cells will reinforce the scaffold and replace it as it degrades. Based on a review of literature, it is theorised that a scaffold with the same regionally varying moduli and microstructure alignment as the meniscus, will present the correct mechanical signals to cells cultured within the scaffold when subject to loading. The cells will then lay down a healthy functional extracellular matrix that mechanically closely resembled the native meniscus.
The focus for this thesis is to develop a scaffold that varies regionally in moduli and has the correct microstructure to direct cell response tailored for the meniscus tissue engineering application. The work completed in this PhD is also aimed at developing scaffold fabrication techniques and scaffold materials that will be used to fabricate a scaffold for the meniscus tissue engineering application. In the process of this development several novel tissue scaffold fabrication methodologies were developed including; an adaptation to the thermally induced phase separation (TIPS) process for photo-curable polymers, and a novel method for controlling isotherms during TIPS to control scaffold pore architectures. In addition to progressing the current state of the art for materials used in soft tissue engineering applications, this study has added novel techniques to the tool box for the fabrication of scaffolds via TIPS for tissue engineering applications.
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